Mental Health Services West (MHSW) is a private non-profit mental health agency offering a wide array of treatment and rehabilitation services. Located in the urban core of Portland, it is the primary mental health provider for the homeless mentally ill of the city. The enclosed manual describes the agency's Dual Diagnosis program for individuals who are homeless or at risk of homelessness. and who have co- existing psychiatric and substance use disorders. The goals of the program are to assist clients to achieve meaningful, productive reintegration into the larger community, and to provide them with the tools to live as positive role models of recovery. The program employs an "Integrated" treatment approach to address mental illness and substance abuse issues simultaneously within one environment. Four features characterize the program: (1) a large array of services; (2) flexible use of program components; (3) use of relapse prevention as an educational tool; and (4) intensive monitoring of clients by Dual Diagnosis staff and case managers. Clients choose from nearly 20 treatment groups as they progress through recovery. They also participate in a myriad of other services, including acupuncture, psychotherapy, medical services. money management, and education and employment services. Clients are expected to achieve a series of positive outcomes as a result of participation in the Dual Diagnosis program. They include decreased incidence of alcohol and drug relapse, improved mental status, improved independent living skills, and a positive and hopeful outlook on life. A plan is also presented for a full-scale evaluation of the program's treatment strategy. The proposed evaluation will take place over a two- year period and include three phases, each with its own evaluation questions and data collection methods. The "Input" phase examines the characteristics of the program and clients that exist independent of the evaluation study. The "Process" phase studies the ongoing implementation of the program. The "Outcome" phase concerns the intermediate and long- term outcomes on clients served by the program and on those from matched comparison groups. Through the use of a quasi-experimental design and repeated measurements over time, this phase will determine whether the program achieved its desired goals and objectives. The evaluation plan emphasizes the complementary value of both qualitative and quantitative data to provide a full picture of the process and outcomes of the Dual Diagnosis program. Qualitative data will emerge from interviews with staff and clients, structured observations, and program records. Quantitative data will include standardized scales, clinical ratings, and program records. Case studies of selected individuals will include both types of data and will cut across all phases of the evaluation plan.